feat(01-01): add Member notes relationship, morph map, and NoteFactory

- Add notes() morphMany relationship to Member model (ordered by created_at desc)
- Register morph map in AppServiceProvider ('member' => Member::class)
- Create NoteFactory with forMember() and byAuthor() state methods

app/Providers/AppServiceProvider.php

@@ -3,7 +3,9 @@
 namespace App\Providers;
 
 use App\Models\Document;
+use App\Models\Member;
 use App\Observers\DocumentObserver;
+use Illuminate\Database\Eloquent\Relations\Relation;
 use Illuminate\Support\ServiceProvider;
 
 class AppServiceProvider extends ServiceProvider
@@ -21,6 +23,11 @@ class AppServiceProvider extends ServiceProvider
      */
     public function boot(): void
     {
+        // Register morph map to protect against namespace refactoring
+        Relation::enforceMorphMap([
+            'member' => Member::class,
+        ]);
+
         Document::observe(DocumentObserver::class);
     }
 }